PCB circuit board tin spraying, also called hot air leveling, is an important process in the production of PCB circuit boards.
The surface treatment of PCB circuit boards can be divided into two types: lead and lead-free:
The so-called lead-sprayed tin refers to the tin in a certain proportion, and the lead will increase the activity of the tin wire during the soldering process. The lead-tin wire is better than the lead-free tin wire, but lead is poisonous and contains lead. The lead is harmful to the human body; the eutectic temperature of lead is lower than that of lead-free. The specific content depends on the composition of the lead-free alloy. For example, the eutectic of SNAGCU is 217 degrees, and the welding temperature is the eutectic temperature plus 30 to 50 degrees, depending on the actual adjustment. The leaded eutectic is 183 degrees. Lead is better than lead-free in mechanical strength and brightness. Therefore, it is not environmentally friendly to have lead and tin, and it is somewhat different from the environmental protection advocated by the world. Therefore, lead-free tin spray was born.
Lead-free tin is an environmentally friendly process. It has very little harm to the human body. It is also a process advocated at this stage. The content of lead in lead-free tin does not exceed 0.5. Lead-free tin has a high melting point, so that the solder joints are firm. a lot of. In essence, lead spray tin and lead-free tin spray are a process. It’s just that the purity of lead is different. Lead-free tin is more environmentally friendly and safer for the human body, and it is also a future development trend. It is recommended that you use it.
Tin spraying is the most commonly used process in PCB circuit boards. This process is more practical. It has good soldering performance, good oxidation resistance, and the price is relatively affordable. It is a very cost-effective process.
